Camera got wet and now has a Error 20 message. Can it be fixed?

Scott Hicks just verifying, your camera is a T6i. For that model Err 20 is really a somewhat generic error "An error prevented shooting. Turn the camera off and on again or re-install the battery." Since it did have an "immersion' you do need to consider this as the cause. Time to start tearing it down and cleaning it with +95% isopropyl alcohol and a small brush.